Process for the preparation of parchment-paper stock from cornstalk pith



Patented Jan. 27, 1931 UNITED STATES PATENT OFFICE ELTON B. DARLING, OI DECATUR, ILLINOIS, ASSIGNOB, BY MESNE ASSIGNMENTS, TO

COBNSTALK PRODUCTS COMPANY, INC

DELAWARE OF NEW YORK, N. Y., A CORPORATION 01B rnocnssron r111: ranrmarron or rancmmn'r-runn s'rocx mom cormsmnx rrrn a Io Drawing.

I 6 growths other than cornstalks, for economic as well as hysical reasons it has been demonstrated that cornstalk pith hasmany points of superiority which make it desirable to use same..

The step of recovering the pith from the cornstalks is well known and does not constitute in itself a part of this invention. Cornstalk pith is washed from the plant with fibrovascular fibers which closely adhere to the pith and are consequently found meshed therewith as it is commercially produced.

The pith is first subjected to a washing operation by which all dirt and foreign matter is removed; The washed and cleansed pith is then subjected to a digestion operation in water and under heat and pressure such as is a set forth in my previous patent application Serial No. 287,651, filed June 22, 1928.

In the course of this digestion operation the pithy mass separates from the fibrovas-- cular fibres, and in the pulpy mass remaining when the digestion is completed the said fibre willl be disengaged from but mixed with the pit 1. i

This pulpy mass is then washed and conveyed onto flat agitated screens of a mesh that will permit the pulpy pith mass to pass through, the stringy fibrovasculaffibres being retained and separated from the pith. 86 The pith then may be bleached by any of the known methods. I have described that the aforesaid pith, either before or after bleaching, is capable of mechanical hydration forming a somewhat gelatinized material which lends itself to the manufacture of parchment paper.

To accomplish this hydration following the bleachin step the material is placed in a beater w ere it is mixed with water heated to I about one hundred and thirty-five degrees Application filed October 1a, 1028. Serial :0. 818,682.

now in condition to be converted into paper by being run through a conventional paper machine forming what is known as vegetable parchment. This is-to be distinguished from the type of vegetable archment where cellulose is'chemically hy rated by means of sulphuricacid and subsequent washing. What I am producing is what is sometimes known as genuine vegetable parchment.

It is obvious that the temperature of one hundred and thirty-five degrees Fahrenheit given above for the water used in the heating operation may be varied to meet the immediate conditions of the operation.

1. The process for the preparation of parchment paper stock from cornstalk pith which comprises cleansing said pithof foreign matter contained therein, subjecting the cleansed ith to a digesting operation in water un er heat and pressure to separate the pith into fibrous and non-fibrous constituents, filtering off the fibrous constituents, bleaching the pithv constituents, and thereupon hydrating the pith by agitating the same with water at 135 F.

2. The process of preparing parchment paper stock from cornstalk pith which com-.

prises cleansing said pith of foreignmatter retained therein, softening said cleansed pith by digesting the same in water and causing, it to se arate into free pith and into fibrous materia separating said fibrous material from said pith, whilediscarding said fibrous material and retaining said pith, bleaching the pith and thereupon hydrating the same by violent agitation at 135 F.

3. The process of treatin cornstalk pith which comprises digesting t e same to cause separation thereof into free ith and fibrovascular material and therea er separatin said fibrovascular fibers from the pith an subsequently hydrating the latter m water at 135 F.

In testimony whereof I have hereunto aflixed my signature.

ELTON R. DARLING. 

